The invention relates to an apparatus and method for flame spraying powder materials by means of an autogenous flame comprising a nozzle carrier which has a burner nozzle and which projects into a guide opening of a preferably tubular attachment body which is provided with coolant guide means surrounding the burner nozzle.
In all known processes for high-energy flame spraying with an autogenous flame, which operate with constriction of the flame in a water-cooled accessory device, problems occur when using accelerating tubes of considerable length due to particles encountering the wall of the tube, such particles resulting in clogging of or damage to the accelerating accessory device, when the apparatus is in operation over a prolonged period. Those problems are to be attributed to the unfavourable turbulence effect in respect of the fine particles in the outer zone of the flame and are heavily dependent on the powder material or the composition, grain size, method of manufacture and morphology of the particles.
If a process which employs a water-cooled accelerating tube is to be used for coating purposes, the accelerating tube has to be designed specifically for each powder material. Hitherto it has not been possible to operate flame spray apparatuses with an accelerating accessory device over a prolonged period without encountering difficulties and disturbances.
The object of the invention is to eliminate those problems.